Various portable devices, such as laptop computers, personal digital assistants (PDA's), portable digital and video cameras, portable music players, portable electronic games, and cellular phones or other wireless devices, require portable power sources. The weight and inconveniences of single-use batteries and rechargeable batteries have motivated efforts to replace those power sources for portable use. Thus, there is an increasing demand for light-weight, re-usable, efficient, and reliable power sources in such applications and in many other applications as well. In attempts to meet these needs, various portable fuel cells have been developed, such as ceramic-based solid-oxide fuel cells, direct methanol fuel-cell (DMFC) systems, reformed-methanol-to-hydrogen fuel-cell (RMHFC) systems, and other proton-exchange-membrane (PEM) fuel-cell systems. Microscale design principles have been applied to the design of portable fuel cells to provide improved power density and efficiency and to provide lower cost. However, microscale fuel-cell designs can be difficult to supply with fuel and oxidant in ways that do not interfere with the purposes of the microscale design. Similarly, it can also be difficult to exhaust depleted fuel and oxidant in a microscale-compatible manner. Although nanoscale manifolding with minimum dimensions below one micrometer has been developed for sensors and other purposes, the scale of such nanoscale manifolding is ill-suited for microscale fuel cell designs. There is a continuing need and a large anticipated market for improved practical compact portable fuel cells with rapid startup times and improved efficiency. There is a particular need for compact portable fuel cells with improved microscale manifolding of supplied fuel and/or supplied oxidant and with improved microscale manifolding for exhausting depleted oxidant and/or depleted fuel from the fuel-cell active region.